CTTsub                  This main function estimates true subscores
                        using different methods based on original CTT
                        scores.
TIMSS11G8M.data         The 2011 TIMSS Grade 8 Mathematics Assessment
                        Dataset
Yen.OPI                 Estimating true subscores using Yen's OPI
Yen.Q3                  Computing Yen's Q3 statistic for unidimensional
                        Rasch, 1-, 2-, and 3-PL logistic IRT models
data.prep               This function prepares data into a required
                        list format
scored.data             Sample scored data
subscore.Wainer         Estimating true subscores using Wainer's
                        augmentation method
subscore.corr           Computing correlation indices for subscores and
                        the total score.
subscore.s              Computing subscores using Haberman's method
                        based on observed subscores.
subscore.sx             Computing subscores using Haberman's method
                        based on both observed total scores and
                        observed subscores.
subscore.x              Computing subscores using Haberman's method
                        based on observed total scores.
test.data               A list of objects that include both test
                        information and subscores.
